In all there are nine players in the squad aged 23 or under, with a combination of injuries and international call-ups handing highly-rated flanker Hamish Watson (21) [pictured] his first start for the club after seven appearances off the bench.

Four of the nine youngsters will start the match: Harry Leonard (20) is promoted from the bench, while Dougie Fife (22), Stuart McInally (22) and Greig Tonks (23) retain their increasingly ever-present places at wing, back-row and full-back.

Head coach Michael Bradley, said: "A number of PRO12 clubs are tested to the limit at this time of the season, both with the attritional nature of the game in terms of injuries and with players selected to represent their country.

"Edinburgh Rugby has proven to be a fantastic breeding ground for talented young players, many of whom will represent Scotland this weekend, while the team picked to play Ospreys will showcase another group of gifted young players coming through who, with time and experience, will grow into hardened, quality individuals capable of delivering winning performances for this club."

He continued: "We were bitterly disappointed to lose at home to Cardiff last weekend because we created enough opportunities to win the game.

'the fact that we created those chances and have already beaten Ospreys this season are positives we can take into this game, but we must be more clinical with our territory and possession if we're to steal a march on the champions in their own back yard."

Grant Gilchrist and Izak van der Westhuizen both sustained ankle injuries in last weekend's home loss to Cardiff Blues, so Perry Parker and captain Sean Cox form a new second-row, with 21-year-old Robert McAlpine joining as the lock replacement on the bench.